The present invention concerns a composition for the coloration of human hair on the basis of an oxidation-dyestuff system reacting with peroxide, providing intensive, permanent colors used either as such, or which can, in combination with further developing and/or coupling substances, be used to achieve additional variations.
The developing substances still used most frequently in hair dyeing compositions are 1,4-diaminobenzene (p-phenylenediamine) and 1-methyl-2,5diaminobenzene (p-toluylenediamine). Use of these substances still may entail problems to the extent that in special cases they can lead to skin sensitization in extremely sensitive persons (so-called "para-allergies").
It has already been attempted to solve this problem by the use of alternative developing substances. To a limited extent, this is possible by the use of tetraaminopyrimidine; however it is then necessary to accept diminished color intensity and reduced possibilities to vary the different shades.
A further solution of the problem, namely the virtual absence of a skin sensitizing effect on one hand and an enhanced level of variations in the preparation of possible shades on the other hand, is achieved by the use of 2-(2'-hydroxyethyl amino)-5-aminotoluene or the water-soluble salts thereof, described in EP-A 615 743, and incorporation of triaminohydroxy pyrimidines, in particular 2,5,6-triamino-4-hydroxy pyrimidine, 2,4,5-triamino-6-hydroxy pyrimidine, 4,5,6-triamino-2-hydroxy pyrimidine or the salts thereof, in particular the sulfates, disclosed in EB 467 026 as developing substances in hair dyeing compositions. Even these changes leave room for improvement with regard to coloration. DE-A 196 14 303 therefore discloses oxidation dyestuff substances containing 2-(2'-hydroxyethyl amino)-5-toluene or the salts thereof as developing substances in combination with 2,6-dichloro-4-aminophenol.
Although this combination permits achievement of a multitude of different shades, the degree of variation as well as color intensity can still be optimized.